#include <stdio.h>
#include <unistd.h>

int global_value = 100;

int main()
{
  pid_t id = fork();
  if(id<0)
  {
    printf("fork error\n");
    return 1;
  }
  else if(id==0)
  {
    int cnt =0;
    while(1)
    {
      printf("我是子进程,pid:%d,ppid:%d | global_value:%d,&global_value:%p\n",getpid(),getppid(),global_value,&global_value );
      sleep(1);
      cnt++;
      if(cnt == 10)
      {
        global_value  = 300;
        printf("子进程已经更改了全局变量了........\n");
      }
    }
  }
  else 
  {
    while(1)
    { 
      printf("我是父进程,pid:%d,ppid:%d | global_value:%d,&global_value:%p\n",getpid(),getppid(),global_value,&global_value );
      sleep(2);
    }
  }
  sleep(1);
  return 0;
}
